When I first began doing childcare, I used Ready-Set-GO! I realized at some point that this was a finite sequence with no expansion opportunity or relationship to our learning objectives. I changed it to 1-2-3!
1-2-3 is the fundamental building block of math, and reinforces the A-B-C of reading. It teaches the rule of sequence/order. Even the 1YOs "get" 1-2-3!
I expand this by changing the number, having the children take turns choosing the number (up to 20 because they like million and trillion), and giving them the option of count down rather than count up, always stating that we go on zero. Now a 5 minute game of back and forth racing a few times a week reinforces several concepts at several cognitive levels in a fun way.